Luton Airport and the London Gliding Club have been operating in close proximity for decades. One would expect everybody flying in the area to know this.
https://www.bbc.co.uk/news/articles/cqevw88d0kxro
Headline:
https://www.bbc.co.uk/news/articles/cqevw88d0kxro
Headline:
Final paragraph:Airline pilot reported near miss on approach to Luton
They (the UK Airprox Board) concluded that although the airline pilot "had been concerned by their perceived proximity of the ASK21", they were "satisfied that normal safety margins had pertained" and "determined that there had not been a risk of collision".